Evaluation of 5 Commercially Available Zika Virus Immunoassays.

Because of the global spread of Zika virus, accurate and high-throughput diagnostic immunoassays are needed. We compared the sensitivity and specificity of 5 commercially available Zika virus serologic assays to the recommended protocol of Zika virus IgM-capture ELISA and plaque-reduction neutralization tests. Most commercial immunoassays showed low sensitivity, which can be increased.

Establishment of a comprehensive and high throughput serological algorithm for Zika virus diagnostic testing.

The previous serological algorithm for Zika virus (ZIKV) comprised screening by anti-ZIKV IgM capture ELISA (MAC-ELISA) for samples collected within 3 months postexposure or onset (MPEO). Samples positive by MAC-ELISA and samples collected beyond 3 MPEO were tested by the confirmatory plaque reduction neutralization test (PRNT), which proved laborious and time-consuming during the 2015 outbreak. Thus, we evaluated several ZIKV ELISAs to establish an anti-IgM and anti-IgG combination for use as a screening tool for all samples prior to PRNT confirmation. The MAC-ELISA or InBios-M in combination with the Euroimmun-G demonstrated sensitivities of 99.1% and 97.2%, respectively, and nonflavivirus specificity of 96.0%. Their cross-reactivities were 71.4% and 50.0%, respectively, for sera positive for Dengue virus antibodies. Due to near-perfect interrater agreement with PRNT and excellent detection of samples collected beyond 3 MPEO, these combinations were recommended as a screening protocol in a new high-throughput algorithm with special considerations for ZIKV diagnostics.

Evaluation of the Diasorin Liaison® XL Zika Capture IgM CMIA for Zika virus serological testing.

Due to the increase of Zika virus (ZIKV) transmission throughout the world, many commercial kits have recently become available to aid in laboratory diagnosis of ZIKV infections in clinical samples. Here, we analyze the fully automated Liaison® XL Zika Capture immunoglobulin M (IgM) assay against the recommended IgM-capture enzyme-linked immunosorbent assay.

Evidence for Host-Genotype Associations of Borrelia burgdorferi Sensu Stricto.

Different genotypes of the agent of Lyme disease in North America, Borrelia burgdorferi sensu stricto, show varying degrees of pathogenicity in humans. This variation in pathogenicity correlates with phylogeny and we have hypothesized that the different phylogenetic lineages in North America reflect adaptation to different host species. In this study, evidence for host species associations of B. burgdorferi genotypes was investigated using 41 B. burgdorferi-positive samples from five mammal species and 50 samples from host-seeking ticks collected during the course of field studies in four regions of Canada: Manitoba, northwestern Ontario, Quebec, and the Maritimes. The B. burgdorferi genotypes in the samples were characterized using three established molecular markers (multi-locus sequence typing [MLST], 16S-23S rrs-rrlA intergenic spacer, and outer surface protein C sequence [ospC] major groups). Correspondence analysis and generalized linear mixed effect models revealed significant associations between B. burgdorferi genotypes and host species (in particular chipmunks, and white-footed mice and deer mice), supporting the hypotheses that host adaptation contributes to the phylogenetic structure and possibly the observed variation in pathogenicity in humans.